This invention relates generally to a method for preparing organosilicon compounds which contain silicon-bonded acylamino-substituted hydrocarbon radicals, to organosilicon compounds obtained therefrom, to curable coating compositions comprising the organosilicon compounds and to a process for providing a substrate with a coating of a cured organosilicon compound. In a preferred embodiment this invention relates to organosilicon compounds bearing silicon-bonded acrylylamino-substituted hydrocarbon radicals.
Organosilicon compounds which contain silicon-bonded acylamino-substituted hydrocarbon radicals, are well known.
U.S. Pat. No. 2,929,829 to Morehouse teaches that organosilicon compounds containing an acylamino group which is attached to a silicon atom through a polymethylene linkage that contains at least three carbon atoms can be prepared by the reaction of an organosilicon compound bearing an aminoalkyl group with a monocarboxylic acid or an ester, halide or anhydride thereof. In the case of monocarboxylic acid halides the reaction is typically conducted in the presence of a hydrogen halide scavenger such as triethylamine. It is well known that the byproduced amine hydrohalide salt is frequently difficult to handle and remove completely from the desired product.
U.S. Pat. No. 4,507,455 to Tangney and Ziemelis teaches that organosilicon compounds that contain acylated N-(aminohydrocarbyl)-aminohydrocarbyl radicals can be prepared by a process which comprise mixing a monocarboxylic acid anhydride with an organosilicon compound which contains N-(aminohydrocarbyl)-aminohydrocarbyl radicals. However, in this process, the desired product is usually isolated by a vacuum distillation step which cannot be used on temperature sensitive compounds such as those containing acrylylated amino-substituted hydrocarbon radicals.
Japanese O.P.I. No. 74113/81 to Takamizawa, et al. discloses photosetting organopolysiloxane compositions which comprise an organopolysiloxane bearing acylamino-substituted hydrocarbon radicals which contain unsaturation and are photopolymerizable. The photopolymerizable organopolysiloxane is produced by the method of Morehouse and has the shortcomings noted above. In addition, even in the presence of a large excess of a tertiary amine such as triethylamine, pyridine, or quinoline to take up hydrogen chloride, some addition of HCl across the double bond of an acrylyl chloride is known to occur, leading to the formation of chloropropionic acids and a corresponding loss of acrylyl activity.
U.S. Pat. No. 4,075,167 to Takamizawa, et al. discloses maleimido group-containing organosilicon compounds which are photocurable. While this method provides fully acylated products from organosilicon compounds which contain monoaminohydrocarbyl radicals, such is not the case with organosilicon compounds which contain N-(aminohydrocarbyl)-aminohydrocarbyl radicals. In the latter case either the secondary amine hydrogen is not acylated or, if it is, an unreacted carboxyl radical from the maleimide reaction remains in the product.
In view of the extensive interest in photocurable organosilicon compounds it would be beneficial to have new and improved methods for the preparation of acrylylamine-substituted organosilicon compounds.